Newt Gingrich accused of patronising Michele Bachmann over her gender in final Republican debate

Newt Gingrich was accused of patronising Michele Bachmann because of her gender, after snapping under pressure from the sole female Republican presidential hopeful in the final debate before voting in the party primary contest.

Amid signs that his poll lead may be slipping, the former House Speaker was attacked by Mrs Bachmann, a Minnesota congresswoman, for taking millions of dollars as a Washington "consultant" after leaving Congress and for tacitly supporting a "barbaric" abortion procedure in the 1990s.

"Sometimes Congresswoman Bachmann doesn't get her facts very accurate," Mr Gingrich said dismissively at one stage, having already told her to stop making "wild accusations".

Describing the remarks as "outrageous", Mrs Bachmann said: "I'm a serious candidate for president of the United States". Asked later if Mrs Bachmann had been targeted for being a woman, Keith Nahigian, her campaign manager, said: "Well, he doesn't say it about any other candidate. It's a unique reaction".

Mr Gingrich was also forced to defend himself from claims by Mr Romney earlier this week that his record as a conservative is "unreliable" and even that he is too "zany" to be US president.

Describing the accusations as "laughable", he said that if Republican activists had been concerned only with "electability" in 1979, they would never have nominated Ronald Reagan, now the party's sainted father.

It came after a Rasmussen poll put Mitt Romney back in the lead in Iowa, the first state to vote next month. Mr Gingrich has led the former Massachusetts governor here since his extraordinary "surge" last month.

Linda Upmeyer, Mr Gingrich's Iowa chairman, conceded later that his ratings could be slipping due to attack advertising from backers of Mr Romney, who can vastly outspend the former Speaker. "When you're the front-runner, they're going to gang up," she said.

Having intensified his criticisms of Mr Gingrich all week, Mr Romney stood back and directed his fire at Barack Obama. Stuart Stevens, his top strategist, told reporters later that as Iowans prepared to caucus, it was "more about who you want to see as president" than who could best a rival Republican.

Mr Romney survived robust questioning over his perceived "flip-flopping" on social issues since his days as a governor and Senate candidate in a Left-leaning state, by playing down his enthusiastic support for gay rights and legal abortion in the 1990s.

But having been accused by Mr Gingrich this week of making $250 million (£160 million) "bankrupting and laying off employees" as a private equity executive, Mr Romney signalled a softening of his claims to be the model businessman, perfect to lead the US out of economic slump. "In the real world, some things don't make it," he said. I believe I've learned from my successes and my failures."